Process of making sugar.



No. 797,965. l PATBNTED AUG. 29, 1995. J. V. P. LAGRANGE.

PRGESS OF MAKING SUGAR. APPLIoATIoN FILED Nov. 1o, 1992.

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JEAN VINCENT PROSPER LAGRANGE, OF PARIS, FRANCE.

PROCESS-0F MAKING. SUGAR.

Specification of Letters Patent.

Patented Aug. 22, 1905;

Application filed November l0, 1902. Serial No. 130,752.

To all whom, it muy concern:

Be it known 'that I, JEAN VINCENT IEos- PEE LAGRANGE, a citizen of theFrench Republic, residing at Paris, France, have invented an Improved1rocess of Manufacturing Sugar, of which the following is a full, clear,and exact description.

My process for the extraction and instantaneous crystallization ofsugar, which forms the subject of the presentinvention, is dependentupon a number of physical phenomena producing absolutely new resultswhich cannot be obtained by any of the methods ordinarily heretoforeknown and used in sugar factories and refineries.

The characteristic feature of my invention is the instantaneouscrystallization in free air of the sugar in a supersaturated syrup underthe combined action of refrigeration obtained by means of a current ofcold water and of the disturbance of the crystallization by theagitation of the mass, whereby boiling in a vacuum apparatus is avoided.This gives results superior tothe ordinary processes, effects a notableeconomy of fuel, and enables the weight of the molasses to be largelydiminished.

In the drawings I have shown an apparatus for carrying out my process.

In the drawings, Figure l is a vertical sectional view, partly inelevation, of an apparatus for carrying out the process; and Fig. 2 is aside elevation of a modified construction of apparatus.

In the drawings, B B indicate agitators revolving in oppositedirections. C indicates the driving-gear for the agitators; D, a shaftcarrying the agitators; E, a fixed pulley; E, a loose pulley; F, aninlet-pipe for water providedwith a regulating-valve; G, an outlet forthe water H, an inlet for steam 5 I, an outlet for steam and condensedwater; M, a thermometer for taking the temperature of the mass, land O adischarge-valve.

The shape of the apparatus may vary. The essential feature is that itshould be jacketed over its entire surface and have means for admittingwater and steam and an agitating device and the other adj unctsmentioned above.

The apparatus seen in Fig. 2 is adapted to be swung over, this 'formbeing adapted for small masses which are treated therein.

In fact I only prepare the syrup in the boiling apparatus, a preparationwhich might also be effected in a boiler in free air.v

I bring it by gradual concentration, reducing the vacuum and withoutforming grains and then in free air, to a temperature of 110o to 115Ocentigrade, and even higher, according to its richness, up to theprecise moment indicated bythe thermometer, when I pour it into a jacketed pan or boiler A, Fig. l, provided with agitators B B, athermometer M, an inlet for water F, an inlet for steam I-I, and otherusual fittings of a like kind, and into the syrup contained in thisapparatus in free air-that v is, without pressure or vacuum-I introducesugar (preferably pulverized) in order to cause by its complete solutiona supersaturation of the syrup. This sugar of supersaturation is addedin the proportion of ten to sixty per cent. of the sugar which the syrupcontains. To destroy equilibrium of this large quantity of sugar held insolution by reason of the maintenance of this high temperature, I cause,as stated above, -two combined actions to intervene-thatjs to say, thedisturbance of the crystallization by a sufficiently rapid movement andby a more or lessy retarded refrigeration by a current of cold water inthe acket A, the volume of which is regulated, and which I shut off atthe precise point of running off, as indicated by the thermometer.

In my experiments I found that in order to obtain the results which Idescribe it was neccesary to venture upon high temperatures,

accurately fixed, without the formation of invert sugar, temperatureswhich alone allow the syrup submitted to them to first becomesupersaturated, and then to give a regular crystallization having largeor small grains by causing the two physical actions which were spoken ofabove to intervene simultaneously-viz., the disturbance of thecrystallization by movement and the lowering of the temperature bymethodical refrigerationwhich cause the precipitation of the sugar inregular crystals. These preliminary and technical explanations wereindispensable before bringing forward my new theories of the formationof the grain independent of the boiling apparatus, which are in absolutecontradiction to the old industrial methods which have been retained upto the present time.

To more fully set forth my invention, I will describe the same in itsapplication to the treatment of beet-root and sugar-cane and also asused in sugar-refineries.

In the treatment of beet-root and sugarcane I take the syrup as itleaves the process well known in sugar-makin as the triple or "multipleeffect, and pass it into the apparatus which ordinarily serves for theboiling to grain. I push the evaporation in vacuum until the ordinarytest shows no formation of grain. I then gradually decrease the vacuumand I observe on the thermometer the temperature, which immediatelyrises. When a 100 centigrade is reached, I stop the vacuum by closingthe communication with the condenser, and always keeping it at thesugar-boiling point I bring the syrup to ebullition, This taking placein free air, I rapidly reach the temperatures of 100, 113, 114, and 115centigrade and even higher, according to the richness of the syrups andthe product which it is desired to manufacture. If, for example, thetemperature of 115 centigrade has been determined by experience fortreating syrup/sfthe first spinnings, the discharge into the jacketedpan is effected in free air, taking care to preserve as much as possiblethe initial temperatures of these syrups and their point ofconcentration, or at least and in every case insuring that thistemperature shall not fall below 100 centigrade. Water and steam can bealternately introduced, according to requirements, into the jacketAofthepan, which enables the temperature of the syrup to be exactlyregulated. An agitator is arranged in the inside to facilitate themixture of the sup ersaturating sugar and to interrupt thecrystallization when the. syrup is supersaturated. This supersaturatingsugar is introduced in any suitable way. A thermometer M, fixed to thepan, shows the progress of the operations. As the solution of the sugarproceeds the thermometer is watched. The cooling which is producedlowers the temperature, which is maintained at a minimum of 108centigrade as long as the supersaturation lasts. When thesupersaturation appears to be complete, the steam-inlet valve is closedand the waterinlet is opened. The agitators continue to work during thewhole of the operation until the completion of the discharge. Thedisturbing action shows as soon as the cold water reaches the jacket andlowers the temperature of the contained mass. This is also the im ortantmoment which should determine t e precipitation of the sugar, theformation and the caliber of the crystals, as well as their extent orproportion. Many factors concur by different actions to obtain theseresults. First, the degree of temperature to which the syrups areconcentrated; second, the degrees of supersaturation of these syrups;third, the time employed in their cooling; fourth, lastly, the degree oftemperature at which the cooling is stopped. Large crystals are producedby dissolving the maximum of sugar of supersaturation in the syrupconcentrated in free air at determined temperatures and by retarding thespeed of current of cold water in the jacket. The crystals form andincrease in size, accordin to the process of the refrigeration indicateby the thermometer, and their yield depends, on the one hand, on thequantity of water which is left in the syrup concentrated in free air-onthe other hand, on the degree of temperature at which therefrigeration-that is to say, the precipitation of the sugar-is stopped.The examination .of the thermometer will also show the density of thecrystalline mass at ythe precise moment when it is passed to thecentrifugals. In fact, it is the opposite to what takes place in thevacuum boiling apparatus, where the density of the mass ltreated isobtained exactly in proportion to the evaporation of the water, while inmy operation, on the contrary, the density of the crystalline mass isobtained by the precipitation of the grain produced by the refrigerationand agitation, and this is whythe indication of the thermometer isvaluable and indispensable for the completion of the operation. To sumup, the quantity of water to be left in the crystalline masses dependsupon the temperature of concentration in free air,l while the finalyield will depend upon the temperature at which the refrigeration of themassthat is to say, the precipitation of the sugaris stopped. If, forexample, it is stopped at 60 centigrade, and this temperature 1smaintained by stopping the current of cold water while the mixing of themass is continued, no more sugar will be precipitated; but the crystalsin sus ension in the mother liquid will simply be ept up or nourished Incertain countries of America, Asia, and Oceania there are sugarfactories not yet provided with vacuum apparatus for the juice and thetreating of the grains in a vacuum. In these factories the juices aresimply evaporated and concentrated in the pans in free air, and when theusual test shows that they have reached the proper point crystallizationis carried on in the vats of the usual storehouses for some days andeven weeks, and a red, impure, and badlycrystallized sugar is extractedby the centrifugal. My new process is adapted to afford a very greatservice to these factories by enabling them after an initialconcentration determined by a thermometer by my method ofsupersaturation and instantaneous crystallization by refrigeration andagitation or disturbance to obtain sugar in grains as white quantity ofsteam is required both for the engine driving the air-pump and forsupplying 'the coils of the apparatus. There is,

therefore, through this difference in the mode of working, great economyof fuel and of time arger yield of the first spinnings,

and a much seeing that the precipitation of the sugar may be pushed asfar as possible, leaving in it a minimum of water and producing a whitesugar well crystallized and very pure.

In the treatment of the second spinnings or thin syrups coming from theturbine the syrups of the second spinnings are, on leaving thecentrifugal machine, returned to the general circulation-that is to say,to the vessels-to be brought after evaporation by concentration in freeair to the temperatures which I have given above until analysisindicates a too'strong proportion of non-saceharine impurities in thesesyrups. An instantaneous and definite liquidationl of them is theneffected by submitting them to the same treatment as that of the firstspinnings, but with this difference, that the temperature-ofconcentration in free air will be higher in proportion as the syrups arepoorer in sugar. The syrups of the second spinnings may also be treateddirectly and their exhaustion obtained by following the course pointedout for the treatment of syrup of the first throwing.

In the countries mentioned above by reason of the aromatic taste of thecane an inferior sugar is manufactured with the second spinnings, whichfor the most part is in the form of an amorphous powder. By my process Ican increase the richness and the yield of the second spinnings andincrease the value of the molasses by transforming it by my method ofsupersaturation into a crystallized and aromatic product. For thispurpose I evaporate the discharge from the centrifugals and concentratethem under the same conditions in free air as the preceding ones. I pushthis concentration to a temperature the higher as the syrup is poorer. Iobtain in the jacketed pan precipitation and instantaneouscrystallization in the conditions described above. After treatment bythe centrifugal of the crystalline mass from these second spinnings,which is donc immediately, the third spinnings is sent at once to theconcentrating apparatus in free air. When the point for discharge intothe pan has been reached, the molasses is supersaturated by making itdissolve the maximum of sugar up to sixty per cent. of the weight ofsugar contained in the said molasses. The grain will be the larger asthe point of supersaturation is higher. Thel normal molasses, which onaccount of its degree of purity could not without previoussupersaturation give any precipitation of grains, is transformed, on theother hand, with the greatest facility and in proportion to the loweringof the temperature into excellent crystals, and if the cooling iscontinued to the moment when the entire mass is' effected a crystallineproduct is obtained of a yellow amber color highly aromatic andexcellent for consumption, containing only two per cent. of water. Byapplying, therefore, my novel methodsv to the manufacture of cane-sugarthe manufacture results in two spinnings, containing all the elements ofthe molasses perfectly crystallized and very suitable for consumptionand highly aromatic, and these transformations are accomplishedimmediately by successive operations, so that directly the lasttreatments of the sugar-cane are completed the factory-fires may beextinguished and all work left off. The same is the case inbeetroot-sugar factories. After the liquidation of the second spinnings,which are taken back a certain number of times and added to the juices,there is obtained or treated directly as the manufacture progresses,after the last beet-roots have been used, a product containing the wholeof the sugar and a residue which is only a fraction of the weight of thenormal molasses.

In using my invention in refineries I obtain by my novel processesrefined finegrained sugar by evaporating first in vacuum the decolorizedmaterial perfectly filtered and limpid, and I then conduct theconcentration by the same method as that which I have described` for thesugar-factory. The pan serving for the reactions is just the same andjacketed, as well as the agitator, thermometers, and inlets for coldwater and steam.

To obtain a fine-grained product, I operate in a somewhat different wayfrom that in the sugar-factory. The proportion of supersaturation ofsugar exercising upon the size of the grain great influence and, on theother hand, the time of the refrigeration also playing a certain part,it is best to dissolve in the concentrated syrup a less proportion ofthe pulverized supersaturation sugar-say about thirty to forty per cent.of the sugar which the syrup contains-and to accelerate the current ofcold water in the jacket, a speed being given to the agitator of abouttwenty-five to thirty turns a minute. If it is desired to mold thecrystalline mass in the form of loaves, thev temperature of this massmust be lowered to S00 centigrade, for instance. It is then reheated to850 or 88 centigrade after having stopped the current of water. It willthen be taken to the vats or vessels in the storinghouse, emplis.) If itis desired, on the other hand, to pour the crystalline mass into whatare well known as Adant molds, or the centrifugals -known as HubnerSchroeder, or others of the kind, the temperature is stopped at about75O centigrade and then raised again to 90O centigrade, the filling intomolds orcentrifugals of the kinds mentioned being then effected in theordinary way. For the manufacture of refined sugar in blocks thetemperature of the mass may be stopped at a lower vpoint to obtain moregrains-say about 700 centigrade-and then the product poured into mixerswhich supply the centrii'ugals, or into small crystallizing vessels,

the masses being allowed to cool for some hours in order to increase theyield. The ine grain is then treated by the centrifugal and should notcontain more than three to four per cent. of Water, so as to enable itto be molded in presses of the kind known as Borssats or others.

Treatment of molasses or low products.- The second spinnings, calledmolasses, cannot, as in ordinary sugar-making, be used over again. Isubmit then, therefore, to a treatment exactly similar in its Workingtothe preceding operation,`but different as consisting of concentrationin free air With supersaturation in the jacketed pan. The degree ofconcentration is pushed to a higher temperature, and the supersaturationis done with a maximum of sugar, and in order to insure a good inalyield the cooling or precipitation of the sugar Ais stopped at a muchlower point. There results a verystrong crystallization of the sugar anda yield showing the most complete exhaustion of the molasses.

What I claim isl. The hereinedescribed improvement in the art ofsugar-making, Which consists in supersaturating in free air the syrup tobe treated by adding sugar thereto and While said syrup is heated asdescribed, then reducing the temperature of the supersaturated syrup andsimultaneously agitating the same until crystallization of the sugartakes place.

2. The herein-described improvement in the art of making sugar Whichconsists in subjecting the concentrated syrup to evaporation in a vacuumfor the period described, then gradually decreasing the vacuum andincreasing the temperature of the syrup as described, then boiling thesyrup, then supersaturating the same in free air by adding sugar to themass and While the latter is in a heated condition, then reducing thetemperature of the supersaturated syrup and simultaneously agitating thesyrup until crystallization of the sugar takes place.

In testimony that I claim the foregoing I have hereunto set my hand this6th day of October, 1902. t

JEAN VINCENT PROSPER LAGRANGE.

Witnesses:

EDMOND LEGOUTURIER, EDWARD P. MAcLEAN.

